The pollen interference experiment series examines the influence of heterospecific pollen application on the shriveling of Echinacea styles. The shriveling of Echinacea styles has previously been considered a signal of compatible pollen receipt, but shriveling can also occur after the application of pollen from other, closely related species without the creation of a viable seed. The pollen interference project aims to determine which species successfully cause shrinkage of Echinacea styles and whether this interference occurs because of an interspecies match in morphology or interparental genetic compatibility.
During the 2019 summer field season, Julie Bailard performed hand-crosses with pollen isolated from individuals of either Heliopsis helianthoides or Ratibida pinnata on styles of Echinacea angustifolia. The goal of this experiment was to determine if heterospecific pollination of Echinacea with closely-related asters resulted in style shriveling. Pollen from each pollen donor was collected in separate microfuge tubes and applied to Echinacea styles the same day, using a fresh toothpick for each donor. In total, 19 Heliopsis and 8 Ratibida sires were crossed with 16 Echinacea dames for a total of 96 interspecies crosses. In 2009, Allegra Halverson applied pollen from Heliopsis helianthoides,Coreopsis, and Carduusonto Echinacea styles and observed that application of Heliopsis pollen often preceded successful style shriveling.
Data/ materials collected:The data are composed of binary outcomes (y or n) representing either successful style shriveling or style persistence for each pollinated style, recorded 24 and 48 hours after initial heterospecific pollen. Each style’s records are paired with the identity of its maternal plant and the species (application 2009 and 2019) and individual identity code (2019) of the heterospecific pollen donor. Datasheets are found in Julie Bailard’s teamEchinacea2019 Dropbox folder in.
This fall, I had the opportunity to present a poster about my recent field research on pollen interference at the Carleton College Summer Research Symposium on October 19. This poster focused on the parts of my experiment that tested whether false sunflower (Heliopsis helianthoides) pollen interferes with reproduction in Echinacea by causing styles to shrivel. My findings suggested that this style shriveling results from a cooperation between dame and sire identity, such that applying pollen from any one false sunflower might succeed in causing style shriveling on one Echinacea plant but not another. This poster summarizes some interesting and promising early results, and I am looking forward to analyzing the presented data further in the coming months. Thank you to everyone at the Echinacea Project who helped make this experiment possible!
This last week at CBG has been busy and exciting! I’ve collected a lot of interesting data about optimal conditions for stimulating germination in rope dodder, checking my scarified seed treatments each day for radicle protrusion. It seems like rope dodder favors balmy incubation conditions, and scarification with acid and boiling water are both effective in ending the seeds’ primary dormancy. If you’d like to know more about my findings, check out my poster below!
Rejoining Team Echinacea again this winter has been wonderful. Carrying out this independent germination project has challenged me to apply my knowledge and skills in experimental design and analysis to a different kind of study than I had ever attempted. I am very grateful to Stuart and Drake for all of their help and guidance along the way. Even though I was only at CBG for two weeks, I have learned so much during that time, and I look forward to bringing everything I’ve learned here into my future endeavors as a scientist.
Hi again, Flog! My name is Julie Bailard, and I’m a senior at Carleton College majoring in biology with a minor in cognitive science. I am excited to be starting my second winter at the Chicago Botanic Garden, after joining Team Echinacea last year as a winter extern and working this summer as an REU field intern. I am very interested in population and community ecology, particularly in the context of conservation and ecosystem health. Much of my previous work with the Echinacea Project has centered around one broad question: How effectively do our current methods of prairie maintenance and restoration protect and promote the health of small plant populations in fragmented habitat?
Staffanson Prairie on a gorgeous August day
This winter, I will be continuing to pursue this question in a new setting: my first germination study, using rope dodder (Cuscuta glomerata) seeds that Drake Mullett collected this summer for his dissertation research on the role of parasitic and hemiparasitic plants in prairie community health. Dodder seeds are “hard” seeds, with a tough outer coat that is impervious to water, leaving the seed dormant until that outer coat is damaged. Researchers aren’t sure how dodder breaks out of this physical dormancy in nature. While certain artificial laboratory methods for scarifying seeds have successfully broken the impervious outer coat in other dodder species, none of these methods have been applied to rope dodder, and very little is known about the optimal conditions for germinating rope dodder seeds. Interestingly, one earlier study of rope dodder distribution in Ohio prairies suggested that novel population recruitment may be positively associated with a recent history of burning. With my experiment this winter, I hope to compare the success of various scarification methods in promoting rope dodder germination, in order to identify the most effective treatment for laboratory germination. If possible, I also hope to consider the results in the context of rope dodder’s natural germinating conditions, including climate, sprouting phenology, and exposure to burning.
Cuscuta glomerata (rope dodder) seeds are about the same size as a poppy seed. And so far, no one knows how to make them sprout!…And sprout is exactly what I want to make them do! So this week, I’ve been designing and setting up a germination experiment to figure out what scarification methods and climate conditions are best for making these seeds grow.
Outside of the lab, I am a clarinetist in the Carleton Orchestra and a consultant in our campus writing center. In my spare time, I also enjoy knitting, practicing T’ai Chi, and playing Muggle Quidditch.
Carleton Quidditch after a Halloween win against St. Olaf (in case you thought I was lying)
After a full morning and afternoon of demography at the Aanenson remnant, followed by some measuring in P1, Team Echinacea ended the working day with an evening of relaxation and fun! We started off with some team shirt tie-dying, led by resident experts Erin and Amy.
Amy displaying a traditional stripe tying technique, while Jay experiments with irregular band designs.Erin demonstrates master tie-dying.
After bagging our newly dyed shirts, we started up preparations for our evening bonfire. Over the course of the past year, the goats have been eating away at the throngs of buckthorn that have been encroaching on our prairie plots. Once the goats have had their fill, all of the dead branches and trunks were gathered together to make this summer’s bonfire pile. With the fire started, the team started shucking corn, cutting sweet potato, and cutting branches for hot dog roasting.
Stuart uses a shovel to lay corn cobs into the coalsRiley roasts a vegetarian hotdog over the corn and coals.
After following our fireside appetizers with Jean’s amazing pasta made with fresh basil pesto, we finished off the night with stargazing and s’mores over the last of the embers. Overall, a great ending to a productive day in the field.
Today, as the Town Hall crew was contemplating our measuring protocol, we realized that our current methods of transporting ourselves down the rows of experimental plots are woefully inefficient. Walking requires that you constantly bend over to check the ground for basal plants and stakes. Crawling puts splinters in your hands and bluestem stalks in your boots. Hopping on one leg may save the airborne ankle from chigger bites, but your ground-bound foot is sure to find a gopher hole. So what does a prairie scientist do, when the time comes to locomote through rows of small plants and tall grass?
Town Hall has the solution: a swing car fleet. The swing car, if you’ve never had the honor of driving one, is a low-riding, 6-wheeled chariot, propelled forward only by your hands on the steering wheel. When we discovered a swing car in a Town Hall closet, the crew knew exactly what we needed to do: test every possible way of driving a swing car to scientifically identify the most efficient method, and assess its utility as a mode of field transportation. Drake demonstrated the remarkably effective “shimmy” method, sidling the chariot back and forth at surprising speed:
Erin, meanwhile, tested the experimental “hang ten” posture, which lets the rider pretend they’re surfing USA, no waves required.
While this method proved to be a wonderful balance exercise, it was woefully inefficient for our transportation purposes, the average distance traveled being -10cm.
To put our swing car to the final test, we had to confirm that operation would be possible in the field. Unfortunately, a thunderstorm outside prevented us from performing this last experiment outside. Instead, we donned our field boots and substituted tall grass duff for shag carpet. A resounding success!
The question of whether swing car riding can outpace walking as the preferred mode of field transportation remains to be tested.
John’s post yesterday provided plenty of updates about Friday’s work on the Hjelm House front. Now it’s my turn to update on the second half of the Western Prairie Fringe Orchid Project, in which Gretel, Stuart, Riley, Drake, and I went out into the wet prairie to assess orchid fitness.
Out in the Nature Conservancy’s wet prairie reserves (which were much drier this time around), we revisited all of the nearly 1000 orchids we identified on the first trip earlier this summer. First, we counted and squeezed all the seed pods to estimate the plant’s seed set, and then we finished shooting GPS points each plant we found. We finished our field work in good time, finishing staking of the South plot in 3 hours, and the Northwest plot in less than 2.
The swollen seed pods of an orchid stalk, with the desiccated flowers still attachedDrake had the chance to meet Pedicularis lanceolata (Pedicularis canadensis is more common around Douglas County)We also stumbled upon a chubby monarch butterfly chomping on some swamp milkweed
Today started off on a slightly less than auspicious footing, as the team’s morning plans of pollinating were largely rained out, as anthers don’t present transferable pollen until they dry. When the morning storms and damp stretched into the early afternoon, we began to realized that our hopes of performing the day’s pollen collection for our pulse/steady pollination experiment were likely to be dashed. Instead, we waited wistfully at the Hjelm House for the stormy weather to pass, working on indoor tasks like data frame cleaning or surv file arranging until the rain subsided enough for phenology data collection.
Over lunch, our discussion naturally turned to the age-old question of how a worm would wear a shirt, if shirts were made with worms in mind. Would they have small, empty sleeves, or would they disavow superfluous appendage coverings in their garments altogether? To aid us in our visualization, Erin handily mustered up her artistic skills and demonstrated exactly how a worm ought to properly attire itself with a tasteful tube top. To properly illustrate her point, she began composing perfect likenesses of the team members’ field outfits, like Jay’s signature flannels and JEGS hat, once adapted to the annelid form.
Lumbricus terrestris Jayicus in its conventional garbEven Darwin, our handy GPS point shooting unit, got in on the wormy fun!
Finally, the rain cleared! We scampered out to P2 to do phenology, and though our pollinating fears from the morning came true when pollen refused to present, the team kept up the momentum by remeasuring and rechecking some of P2’s most interesting and bizarre plants. We circled back to basal plants with leaves half a meter long, flowering plants with four heads on one stalk, and plants with more than 10 rosettes and 50 basal leaves (a rarity when most plants have only two or three rosettes with less than 10 leaves total). With half of P2’s 80 rows triple-checked, we shifted gears to remnant population demography, as Erin and Shea trained Jay and me in the system of PBORY flag ordering and surv file code naming. As we identified and recorded flowering plants, we started adapting the lyrics of AC/DC’s T.N.T. on the fly to fit our demography PBORY protocol (pronounced P-Bor-Ee). Our chorus went something like the following:
Cuz it’s PBORY Gotta stake it right PBORY Then flag the flowers in white PBORY Count rosettes and heads PBORY See how a population spreads!
Today, we were unfortunately rained out of some of our planned weekend fieldwork. Though we were hoping to do some more crosses for the pulse/steady pollination experiment, early morning rainstorms settled in before we could head out to P2, and they stayed through much of the day. Wet pollen is not the easiest to effectively swipe on styles, while rainy weather can also delay pollen presentation on anthers. Instead, Stuart decided to call off the day’s fieldwork, leaving the Town Hall crew to spend the morning inside and dry. While Erin, Jay, and I were puttering around Town Hall enjoying the sounds of raindrops on the windows, Amy and Riley were making their way back from their own weekend excursions further south near the Twin Cities.
At least the sunny weather held out long enough for Erin, Jay, John, and Stuart to do a round of crosses on steady treatment plants yesterday, all while I collected the last of the style persistence data from my own interspecific crosses. I’m excited to start crunching the numbers and considering the results!
Wondering why this Echinacea head is so *colorful*? Each paint color in each row labels a different set of crossed florets, which received pollen from either Heliopsis helianthoides or Ratibida pinnata.
Just before the stormy weather set in, we also took the chance to enjoy a lovely weekend evening on the shore of Elk Lake.
Erin at Elk Lake, enjoying a sunset swing in her hammock
Today was Phenology Phriday! Much of the team recorded flowering progress in P1, P2, and P8 this morning, where Erin found an adorable nest of baby Field Sparrows!
Amy and I split off to check on the plants in the remnants. Near East Elk Lake Road, I also practiced collecting Heliopsis helianthoides pollen for my upcoming pollen interference experiment. Excited to start my crosses next week!
The other teammates were also making progress on their projects. Jay finalized details for data collection for the Ash Annihilation experiment. Drake continued collecting seeds from parasitic Comandra and a variety of host plants. Meanwhile, Jennifer and Miyauna tried dipping bees in fluorescent dye to follow their activity around the plots. I must say, their new costumes look lovely!
In the afternoon, Shea, Miyauna, and Jennifer pinned the bees they caught earlier this week, while much of the team returned to P8 for a full afternoon of leaf measuring. We’ve nearly canvased the whole plot of basal plants with fresh toothpicks, so thoroughly that we almost ran out of toothpicks! Overall, a productive day in the field.
